Ive never seen before - have any of you?

[bigboy]

Went to a job with supervisor , customer complained that boiler stopped working, error code said pressure in heating system too low, (obviously sealed system). Customer also wanted a rad changed. Tried to drain down system first to change rad, and valves, drained down for over 30 mins( about 3-4 rads), still more water, so just shut valves and replaced rad, assumed filling loop must be on, so checked but no, so disconnected loop.so then assumed plumber who installed it must not have disconnected the f+e tank, so went to check on roof, guess what no f+e tank.
Checked boiler read 0.5bar, so filled filling loop pressure went to 1.3 bar so shut loop, within 3 mins pressure dropped to 0.5 bar, checked twice.
Supervisor goes some doughnut has connected an indirect cold water supply to the sealed system, as if the mains was connected then pressure would be high constantly. Now the silly thing is the indirect cwst is massive and serves 6 other flats in the building, so sealed heating system is possibly backing into indirect supply. Supervisor warned customer only way to be sure is to expose pipework, everything is boxed in and concealed. Supervisor thinks customer must of fallen out with plumber, and plumber had the last laugh. Can any of u think of any other reasons why pressure keeps on dropping to 0.5 bar. No leaks anywhere either.

 

[justlead1]

Hi. Is it a combi? Is there an indirect cylinder in the circuit?

 

[PlumbBobBob]

is it a block of flats or a large house converted to flats? maybe rad pipes run into another flat or flats.

 

[bigboy]

sorry should have said, vented in direct hot water system, already thought coil had split but all hot water clear, and after draining heating water from rads was clear as well.
customer been using immersion for hot water,

 

[bigboy]

large house converted to flats, customer only bought flat recently

 

[Ultimate P & H]

Supervisor goes some doughnut has connected an indirect cold water supply to the sealed system, as if the mains was connected then pressure would be high constantly.

How high above the boiler is the CWSC? If it's a couple of floors then that'd be about right for 0.5 bar, if its four or five floors then even the standing head is going to be over 0.5 bar. A split cylinder coil is possible, isolate the cylinder and open the hot taps, in theory it would depressurise the heating if the coils split. I have even seen a coil thats completly separated so you can get full flow through it!

Have to say though, I reckon your supervisor is spot on the money.

 

[bigboy]

cwsc is literally on the roof about 2 floors above boiler in kitchen, this is the top floor flat,

 

[Ultimate P & H]

So about 5 metres above the boiler? If so that's 1/2 bar of standing pressure. Check the hot water coil mate, if it's not that then a 'rogue' indirect connection is about all that's left.

 

[REDSAW]

i'd go with the dohnut principle and steveb, piped through neighbors floor or supply etc. £££££££££££££££3

 

[Ultimate P & H]

Bear in mind that a well maintained and treated heating system will have clean water anyway, so dirty water or not is not necessarily a valid conclusion.

 

[justlead1]

Hi. If you can find the time? Pump it up with some air or inert gas (via a cylinder perhaps) check out bubbles in the CWSC coming from cold distribution connections. Just to prove the problem. Then start ripping the place apart.

 

[bigboy]

Bear in mind that a well maintained and treated heating system will have clean water anyway, so dirty water or not is not necessarily a valid conclusion.

when we first drained down the water was dirty, but soon became clear, i know cos it was my job to stand in front of the toilet and tell the supervisor when the water had finished!

but will definately suggest to the gaffer to isolate the cylinder, as ultimate p + h has suggested, but assumed this couldnt be it as hot water taps water was fine - no dis-colouration at all. hope the supervisor takes me back to have a look.

also if as steveb and redsaw suggest then its a right problem as all pipework is concealed.

forgot to mention we also drained down the rads the next day for over 45mins, and checked if the cwsc was refilling , but being connected to so many flats we couldnt be sure, as where acting on behalf of the customers estate agents and they didnt give us permission to contact other tenants in the building.

 

[bigboy]

Hi. If you can find the time? Pump it up with some air or inert gas (via a cylinder perhaps) check out bubbles in the CWSC coming from cold distribution connections. Just to prove the problem. Then start ripping the place apart.

will definately suggest this as well, cheers for all advice from everyone, will post again once course of action has been planned

 

[WaterTight]

i'd go with the dohnut principle and steveb, piped through neighbors floor or supply etc. £££££££££££££££3

Or get redsaw to fix it. He'll do it for £3.

 

[bigboy]

evening all, just an update, coil had split, fitted new cylinder this week, everything all good. was still shocked at how clean the water was though from the taps,